1. Field of the Invention
This invention relates generally to alternative input mechanisms to computer systems, and more particularly to visually tracking a light, wherein a change in the light triggers an action on the part of the computer system.
2. Description of the Related Art
There has been a great deal of interest in searching for alternatives to input devices for computing systems. The keyboard and mouse for the desktop computing system are taken for granted at this time. However, for interactive entertainment applications in a “living room” environment, the keyboard and the mouse have failed to gain widespread acceptance.
Tracking of moving objects using digital video cameras and processing the video images for producing various displays has been attempted also. However, these systems tend to rely on having a plurality of video cameras available for developing positional information about the object based on triangulation. The cost for these systems becomes prohibitive for their introduction into the “living room” environment.
However, in spite of the above knowledge and techniques, problems continue to hinder successful object tracking, and a particularly difficult problem is extracting precisely only those pixels of a video image which correspond unambiguously to an object of interest. For example, although movement of an object having one color against a solid background of another color, where the object and background colors vary distinctly from one another, can be accomplished with relative ease, tracking of objects, even if brightly colored, is not so easy in the case of multi-colored or non-static backgrounds. Changes in lighting also dramatically affect the apparent color of the object as seen by the video camera, and thus object tracking methods which rely on detecting a particular colored object are highly susceptible to error or require constant re-calibration as lighting conditions change. The typical home use environment for video game programs demands much greater flexibility and robustness than possible with conventional object tracking computer vision systems.
Thus, an alternative input device must be able to be tracked under the home use environment by a single relatively inexpensive camera in order to become widely accepted. Additionally, the alternative input device must be convenient to use. While a glove worn on the hand of a user, where the glove includes sensors that are tracked by a camera to capture input, has been trialed, users have not embraced the glove. One of the reasons for the lack of enthusiasm for a glove is the inconvenience of having to continually remove and put on the glove. Furthermore, the alternative input devices described above do not easily adapt themselves to being able to indicate a mode change, functionally similar to a mouse click.
Thus, there is a need to solve the problems of the prior art to provide an input device capable of being tracked by a single video camera, wherein the input device is convenient for the user and capable of indicating a mode change.